AST-A105 1nd EditionExam # 1 Study Guide Lectures: 7-13Lecture 7 (February 11)- Sun is a typical star- a self-gravitating sphere of hot gas- Luminosity- energy output per time Lecture 8 (February 13)- Standard Solar Model- computer model for the interior structure of the Sun- Hydrostatic Equilibrium- outward gas pressure force balances inward force of gravity- Thermal Equilibrium- energy radiated from the photosphere of the Sun is replaced by an internal energy release Ordinary burning (oxidation) can only power the Sun for a few thousand years. - Hydrogen Fusion- 4 Hydrogen nuclei (protons) fuse to form 1 helium nucleuso 4 H 1 He + energyLecture 9 (February 18)- Atmosphere of the Sun:o Photosphereo Chromosphereo Transition Roado CoronaLecture 10 (February 20)- Sunspots- Sunspots- cooler regions (4500 K) in photosphere- Sunspot cycle- average number of spots varies with a period of approximately 11years.- Sunspot maximum- last occurred in late 2000i. Flare- violent release of energy and particles from a small region in solar atmosphere- Solar Wind- stream of mostly protons and electrons escaping from coronaii. Flow out through solar systemiii. Aurora- northern and southern lights near Earth’s polesLecture 11 (February 25)- Solar Neutrinoso Neutrino- a very low mass, neutral particle that travels near the speed of lighto Parallax- the apparent shift of an object due to a change in viewpoint.Lecture 12 (February 27)- Star- a fixed luminous point in the night sky that is a large, remote incandescent body like the Sun. - Luminosity (L)- energy per time radiated by star- Inverse Square Law for Radiation- energy radiated by star that spreads out over an area as it increases by d2. - Ideal Gas Law- obeyed by normal gases: air in this room, as well as hot, ionized gas inside the Sun. Lecture 13 (March 4)- Stellar Spectra- spectral classification based on absorbtion lines.- Spectral Sequence –O B A F G K
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